Oxidative stress plays a critical role in cognitive dysfunction and neuronal death associated with neurodegenerative diseases. Nrf2 is a transcription factor that plays a key role in cellular resistance to oxidative stress, but little i known about the physiological signals that regulate Nrf2 activity in the brain or how Nrf2 impacts neuronal function. My laboratory uses the model C. elegans to study new signaling pathways that modulate presynaptic function. We recently identified the Nrf2 homolog, SKN-1, as a regulator of presynaptic structure and function. We found that SKN-1/Nrf2 functions cell non- autonomously to regulate neurotransmitter secretion from neuromuscular junctions. We also found that neuroendocrine signaling from the nervous system confers organism-wide protection from the toxic effects of oxidative stress by activating SKN-1/Nrf2 in distal tissues. Here we seek to uncover the cellular and molecular mechanisms by which bidirectional communication between the nervous system and distal tissues promotes an adaptive response to oxidative stress through the regulation of neurotransmitter secretion. In Aim 1, we will determine how SKN-1/Nrf2 activity is positively regulated by neuropeptide release from the nervous system. In Aim 2, we will determine how reactive oxygen species promote neuropeptide release in vivo. In Aim 3 we will determine how synaptic transmission is negatively regulated by cell non-autonomous SKN-1 activation. Nrf2 activation protects neurons form death in a variety of neurodegenerative disease models, and our research may uncover new endogenous activators of Nrf2, which may lead to the development of new therapeutics that can prevent or treat these diseases.